Welded heat exchange plate



March 22, 1966 A. CHRISTENSEN WELDED HEAT EXCHANGE PLATE 5 Sheets-Sheet 1 Filed Nov. 27, 1965 March 22, 1966 A. CHRISTENSEN WELDED HEAT EXCHANGE PLATE 5 Sheets-Sheet 2 Filed Nov. 27, 1963 INVENTOR /,m/ Kira/01M, BY

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Filed NOV. 27, 1963 III United States Patent 3,241,604 WELDED HEAT EXCHANGE PLATE Axel Christensen, Morton Grove, 111., assignor to Dole Refrigerating Company, Chicago, 111., a corporation of Illinois Filed Nov. 27, 1963, Ser. No. 326,623 2 Claims. (Cl. 165--47) The present application is a continuation-in-part of my oopending application Serial No. 189,610, filed in the United States Patent Oflice on April 23, 1962, for Welded Heat Exchange Plate, now abandoned.

The invention relates to an improved heat exchange plate in which adjacent heat exchange tubes are in direct contact wtih each other.

A primary purpose of the invention is a heat exchange plate of the type described including improved means for connecting adjacent tubes.

Another purpose is a heat exchange plate in which adjacent tubes may be connected either in series or in parallel.

Another purpose is a heat exchange plate of the type described which may be used either in cooling or in heating.

Another purpose is a heat exchange plate in which adjacent tubes are so connected that the structure is rigid and need not be encased for strength.

Another purpose is to provide a plate with a flat surface, desirable in certain heat transfer applications.

Another purpose is to maintain a maximum primary heat transfer surface in one plane.

Another purpose is to maintain an even heating or cooling surface from and throughout a flat surface.

Other purposes will appear in the ensuing specification, drawings and claims.

The invention is illustrated diagrammatically in the following drawings wherein:

FIGURE 1 is a top plan view of a heat exchange plate of the type described;

FIGURE 2 is a partial plan view of the first step in joining adjacent tubes of the plate in FIGURE 1;

FIGURE 3 is a partial perspective of the second step in joining adjacent tubes of the plate in FIGURE 1;

FIGURE 4 is a partial enlarged perspective of the heat exchange plate in FIGURE 1, showing a number of joined tubes;

FIGURE 5 is a top plan view of a second form of heat exchange plate;

FIGURE 6 is an enlarged partial perspective, similar to FIGURE 4, showing the method of joining the tubes of the plate in FIGURE 5; and

FIGURE 7 is a plan view, with parts broken away, of a variant form. V

This invention is particularly concerned with the construction of a heat exchange assembly, often referred to as a heat exchange plate. The plate or assembly may be used in refrigeration or in heating. When used in refrigeration the plate may be characterized as a heat exchanger for circulation with secondary refrigerant such as a brine, or as an evaporator for circulation of a primary refrigerant such as ammonia or any siutable volatile refrigerant. When used in heating the plate would serve as a a heating panel.

It will be understood that the plate or coil structure, as shown in FIGURES 1 to 6, inclusive, may be used with or without a surrounding shell. In FIGURE 7 and following the plate structure of FIGURES 1 to 4, inclusive, is shown as housed in a flexible walled housing, the interior of which may be reduced to less-than-atmospheric pressure, whereby to force opposite side walls of the housing against the tubular structure of FIGURE 1 and following. It will be understood that if a plate having an over-all thickness greater than the thickness of the tubular structure is desired, any suitable spacing means, ribs or the like, may be employed. It will also be understood that, if desired, a liquid may be employed partially to fill the space within the outer housing, whereby to provide a body for storage of cold, or a temperature transmitting film between the inner surfaces of the casing walls and the opposed tubular structure.

Considering FIGURES 1 through 4, a plurality of tubes 10, which may be either square or rectangular in cross section, but preferably square, are joined together to form a heat exchange plate 12. The sides of adjacent tubes are in contact wtih each other throughout their length. The tubes are not spaced apart as in conventional in presently-used serpentine coil heat exchange plates. An inlet 14 may be formed in one of the outside tubes and an outlet 16 may be formed in the other outside tube. As shown in FIGURE 1, the tubes are connected in series so that there will be a continuous tortuous flow path for the heat exchange fluid from the inlet 14 to the outlet 16.

FIGURES 2 and 3 illustrate the method of connecting adjacent tubes in the structure of FIGURE 1. The first step in joining two tubes is a bevel off the ends of the tubes so that each end is inclined inwardly toward its connecting tube, thereby forming a generally V-shaped indentation. The beveled ends are indicated at 18 in FIGURE 2. Next, the inner edges of the tubes to be connected are welded together, as at 20. A cap 22, which may be generally triangular in shape and may have a cross section along its altitude generally the same as the cross section of each of the tubes, so as to provide a continuous unrestricted flow path between adjacent tubes, is then seated in the triangular-shaped opening formed by the beveled ends 18. After the cap 22 is seated, it is welded to each of the tubes along all adjoining edges. As shown in FIGURE 3 there will be a weld along adjoining slanted edges 24 and along the outside edges 26 of the tube ends. After the assembly steps described above, adjacent caps may be tack welded to one another, as at 27, to give rigidity to the unit.

The heat exchange plate shown in FIGURES 5 and 6 is arranged so that the tubes are in parallel, rather than in series, such as is shown in FIGURES 1 through 4. A heat exchange plate 28 is formed by a plurality or group of individual tubes 30. Each of the tubes may be either square or rectangular in cross section. In any event, the tubes each have four sides and all the corners generally form degree angles. Spaced headers 32 and 34, generally perpendicular to the direction of the parallel tubes 30, may be used to form an inlet 36 and an outlet 38. As shown in FIGURE 6, each of the headers has three sides over a major portion of their length, with the open fourth side 40 being positioned opposite the end of each of the tubes 30. Each of the headers thus opens into or is in communication with each of the tubes 30 to form a plurality of parallel fluid flow passages between the inlet 36 and the outlet 38. As a matter of convenience, if the structure is shown as made in FIGURES 5 and 6 the extensions 36 and 38 may be provided with inner side walls 36a and 38a, in effect, converting a channel into a tube.

In order to assemble the tubes in the heat exchange plate of FIGURES 5 and 6, the tubes are all cut off so that they are the same length. Next, the adjoining edges of adjacent tubes are welded together, as at 42. After the tubes have all been welded together to form a single unit, the headers are positioned such that their open side is opposite the ends of the tubes 30. Then, each of the adjoining edges of the tubes and headers, as at 44, are welded or otherwise suitably connected together. A cap or the like 46 may then be placed on the end of the headers to complete the structure. It is preferred that the cross sectional area of each of the headers be larger than the cross sectional area of the tubes, although, under some circumstances, as shown in FIGURE 5, it might be the same.

Whereas, under many circumstances, it is advantageous to employ the above illustrated plate structures as a complete plate or heat exchanger, under some circumstances I find it advantageous to use the herein described coils in connection with an outer plate housing. For example, in FIGURE 7 I illustrate a coil structure which may be considered identical with that shown in FIGURE 1. Surrounding it is a plate housing or outer casing having a pair of generally parallel walls, of which one wall 30 is illustrated as broken away to show the coil structure within. An opposite and generally parallel plate side wall is employed, the edges of which are shown as at 31. Connecting the two plates 30 and 31 is a circumferential edge wall structure generally indicated as 32. It may be separately formed, but may advantageously be formed by bending edges of the plate side wall 30. It will be understood that the casing thus formed is gas-tight, and a fitting 33 may be employed to permit the insertion of liquid into the space within the outer casing and, also, to permit the Withdrawal of air therefrom. Thus I may provide a less-than-atmospheric pressure within the plate, whereby the outside atmospheric pressure will press the plate side walls 30 and 31 toward each other and into snug contact with the coil structure generally indicated at 10. If desired, any suitable spacing means may be employed, whereby the outer plate structure may be of greater thickness than the coil. The fitting 33 may be of the ball valve type, whereby, by any suitable tool, the ball may be moved out of contact with the valve, and a liquid may be supplied to the interior of the plate, or air may be withdrawn from within the plate, through the single fitting 33.

The use, operation and function of the invention are as follows:

I have shown a heat exchange plate in which the adjacent tubes, either square or rectangular in cross section, preferably square, are positioned adjacent to each other with adjacent walls in complete contact throughout the tube length. The construction shown in FIGURES 1 through 4 is particularly advantageous for use as an evaporator plate in a refrigeration system, although it may have other uses. The cross section of the tubes are generally equal throughout and the cross section of the connections between adjacent tubes are the same as the tubes so that there are no restrictions or enlargements in the path of fluid flow between the inlet and the outlet. This is particularly advantageous in a cold plate where restrictions and/or enlargements are undesirable.

Of particular importance is the means for connecting adjacent tubes. The connecting caps do not enlarge the total length of the tubes and yet provide a compact and fluid-tight connection between adjacent tubes. The ends of each of the tubes are beveled or inclined inwardly toward their connecting tube. The tubes are then welded together along their inner edges. The closure means, a generally triangularly shaped cap member, is then inserted in the triangular-shaped opening between adjacent tubes and is then welded to adjoining edges of the tubes. In this way, a simple and yet strong series connection is provided between adjacent heat exchange tubes.

The heat exchange plate shown in FIGURES 5 and 6 may also be used in a refrigeration system, but has found particular use as a heating plate. In this case all of the tubes are connected in parallel, rather than in series. Again the simplicity of the construction and the means for connecting adjoining tubes is important. Each of the tubes is cut off or originally formed so that they are of the same length. The headers, which may have the same cross sectional area as the tubes, but are preferably larger, and which have three sides along most of their length, are connected to the ends of the joined tubes so that each tube opens into the header. When the tubes are connected in parallel as shown in FIGURES 5 and 6, and are used as a heating coil, all points in the coil will receive the heating fluid at generally the same temperature and there will not be any extreme variations in temperature over the plate, as may be true if the plate were series connected.

With reference to the operation of the structure of FIGURE 5, and assuming that 36 is the inlet and 38 is the outlet, it will be observed that the various crosspassages 30 are of equal length. The header 32 delivers fluid to all of the cross tubes 30 and the flow is uniform through the tubes to the opposite header and thence to the discharge passage. Note that the fluid entry is at one corner and the fluid escape is at the diagonally opposite corner. Thus the paths through the individual length are of uniform length throughout and there is no tendency to short-circuit.

Of particular advantage in the form shown in FIG- URES 5 and 6 is the simplicity of the tube connection. Adjoining edges of each tube are welded together after which the header is welded along the outside edges of the joined tubes.

The plate construction in both forms of the invention is advantageous for its strength. There is no necessity of enclosing or encasing the plate structure to strengthen it. However, as earlier discussed, the structure herein shown may advantageously be employed within an outer casing. And such a casing may be employed in connection with an internal less-than-atmospheric pressure. Additional spacing means may be employed where necessary. A liquid component may also be employed in the space between the outer casing and the coil structure, if desired, for storage of cooling effect, or to form a heat transmitting film.

Whereas the preferred form of the invention has been shown and described herein, it should be realized that there are many modifications, substitutions and alterations thereto within the scope of the following claims.

I claim:

I. A smooth surfaced heat exchange assembly assembleable from like heat exchange members, said assembly including, in combination,

a plurality of heat exchange members,

each of said members having a rectangular external cross sectional configuration formed by four parallel single line edges,

said members being disposed in parallel abutting contact one with the other along their length to thereby form two parallel smooth plane surfaces having no indentations or irregularities,

the ends of each adjacent pair of heat exchange members taken at one end of the assembly forming a generally V-shaped indentation opening outwardly from the bottom of said indentation,

the end edges of the abutting walls of each of said pair of adjacent heat exchange members being joined in fluid tight engagement,

closure means forming an externally sealed, internally unrestricted fluid flow path from one another to the other member of said pair of members,

said closure means having a generally U-shaped cross sectional configuration and a pair of opposed wall portions whose external faces are disposed in parallelism with one another, and a distance apart equal to the distance between the exterior faces of the heat exchange members,

the opposed wall portions generally conforming to the configuration of the indentation formed in the associated ends of said heat exchange members whereby a smooth surface will be provided when the closure means is secured fluid tightly to its associated pair of heat exchange members,

the ends of each adjacent pair of heat exchange members at the opposite end of the assembly, offset by one heat exchange member, being similarly formed and associated with similar closure means,

to thereby enable said heat exchange members to be connected in series to provide a continuous, serpentine, fluid flow path from inlet to outlet of the assembly.

2. The structure of claim 1 further including an outer housing of flexible walls arranged in gas tight relationship about the heat exchange members, and

means for enabling the pressure within the housing to be reduced to less than atmospheric whereby the housing walls may be urged against the heat exchange members by the -difierence in pressure between the inside and outside of the outer housing.

References Cited by the Examiner UNITED STATES PATENTS 2,436,390 2/1948 Kleist. 2,521,475 9/1950 Nickolas 165175 X 2,690,653 10/ 1954 Kleist. 3,024,521 3/1962 Polk 165--168 X FOREIGN PATENTS 560,529 7/ 1923 France.

3/ 1923 Great Britain. 

1. A SMOOTH SURFACED HEAT EXCHANGE ASSEMBLY ASSEMBLEABLE FROM LIKE HEAT EXCHANGE MEMBERS, SAID ASSEMBLY INCLUDING, IN COMBINATION, A PLURALITY OF HEAT EXCHANGE MEMBERS, EACH OF SAID MEMBERS HAVING A RECTANGULAR EXTERNAL CROSS SECTIONAL CONFIGURATION FORMED BY FOUR PARALLEL SINGLE LINE EDGES, SAID MEMBERS BEING DISPOSED IN PARALLEL ABUTTING CONTACT ONE WITH THE OTHER ALONG THEIR LENGTH TO THEREBY FORM TWO PARALLEL SMOOTH PLANE SURFACES HAVING NO INDENTATIONS OR IRREGULARITIES, THE ENDS OF EACH ADJACENT PAIR OF HEAT EXCHANGE MEMBERS TAKEN AT ONE END OF THE ASSEMBLY FORMING A GENERALLY V-SHAPED INDENTATION OPENING OUTWARDLY FROM THE BOTTOM OF SAID INDENTATION, THE END EDGES OF THE ABUTTING WALLS OF EACH OF SAID PAIR OF ADJACENT HEAT EXCHANGE MEMBERS BEING JOINED IN FLUID TIGHT ENGAGEMENT, CLOSURE MEANS FORMING A EXTERNALLY SEALED, INTERNALLY UNRESTRICTED FLUID FLOW PATH FROM ONE ANOTHER TO THE OTHER MEMBER OF SAID PAIR OF MEMBERS, SAID CLOSURE MEANS HAVING A GENERALLY U-SHAPED CROSS SECTIONAL CONFIGURARION AND A PAIR OF OPPOSED WALL PORTIONS WHOSE EXTERNAL FACES ARE DISPOSED IN PARALLELISM WITH ONE ANOTHER, AND A DISTANCE APART EQUAL TO THE DISTANCE BETWEEN THE EXTERIOR FACES OF THE HEAT EXCHANGE MEMBERS, THE OPPOSED WALL PORTIONS GENERALLY CONFORMING TO THE CONFIGURATION OF THE INDENTATION FORMED IN THE ASSOCIATED ENDS OF SAID HEAT EXCHANGE MEMBERS WHEREBY A SMOOTH SURFACE WILL BE PROVIDED WHEN THE CLOSURE MEANS IS SECURED FLUID TIGHTLY TO ITS ASSOCIATED PAIR OF HEAT EXCHANGE MEMBERS, THE ENDS OF EACH ADJACENT PAIR OF HEAT EXCHANGE MEMBERS AT THE OPPOSITE END OF THE ASSEMBLY, OFFSET BY ONE HEAT EXCHANGE MEMBER, BEING SIMILARLY FORMED AND ASSOCIATED WITH SIMILAR CLOSURE MEANS, TO THEREBY ENABLE SAID HEAT EXCHANGE MEMBERS TO BE CONNECTED IN SERIES TO PROVIDE A CONTINUOUS, SERPENTINE, FLUID FLOW PATH FROM INLET TO OUTLET OF THE ASSEMBLY. 